getDrawFaceOutlines

Returns the flag that controls whether or not the faces making up area
segments will be drawn with outlines. The default value is
true. When anti-aliasing is on, the fill area for the
faces will have some gray shades around the edges, and these will show
up on the chart as thin lines (usually not visible if you turn off
anti-aliasing). To mask this, the rendering engine can draw an outline
around each face in the same color (this usually results in cleaner
output, but it is slower and can introduce some minor visual artifacts
as well depending on the output target).

findValueRange

Returns the range (for the value axis) that is required for this
renderer to show all the values in the specified data set. This method
is overridden to ensure that the range includes the base value (normally
0.0) set for the renderer.